\documentclass{standalone}
	
\usepackage[siunitx]{circuitikz}

\begin{document}

\begin{circuitikz}[scale=1., transform shape, american voltages]
    \draw (-2.5,-.5) -- (1,-0.5) -- (1,2.5) -- (-2.5,2.5) -- (-2.5,-0.5);
    \draw (-3,0) node[anchor=east] {$sn2$};
    \draw (-3,2) node[anchor=east] {$sn1$};
    \draw (-2, 2) to[open, v^=$\ V$] (-2, 0);
    \draw (-3, 0) to[short, *-o] (-2, 0);
    \draw (-3, 2) to[short, *-o] (-2, 2);
    \draw (1.5,0) node[anchor=west] {$n2$};
    \draw (0,0) to[short, -*] (1.5,0);
    \draw (0,0) to[cspst=$f(V)$] (0, 2);
    \draw (1.5, 2) node[anchor=west] {$n1$};
    \draw (0,2) to[short, -*] (1.5, 2);
\end{circuitikz}

\end{document}
